This invention relates to the art of aqueous laundering of soiled fabric articles and, more particularly, to a method of pre-treating such articles to enhance the cleaning thereof upon subsequent laundering and to apparatus for achieving such purpose.
It is of course well known that fabric articles such as clothing, towels, bed sheets and the like are soiled by wearing or use thereof. Further, it is common practice to set aside such soiled fabrics until such time as they may be laundered in a washing machine designed for such purpose using a commercially available detergent alone or in combination with additional laundering aides such as fabric softeners and bleaches. In this fashion soiled articles are restored, to as great an extent as possible, to the condition possessed before use. However, it is also well recognized that restoration of fabrics by this method is typically incomplete and, in particular cases, unacceptable. Many approaches have been taken to address the short comings of the results achieved by conventional laundering, both within the process itself and external to it. Internally, advancements in both washing machine design and operation, as well as improvements in formulations of cleaning agents and additives take place on a continuing basis. In addition to these advances, "pre-soak" cycles on washing machines, in which soiled articles are allowed to stand in an aqueous bath for an extended period, afford a launderer yet another tool to improve cleaning performance. External to the washing process itself, advancements in fabric compositions, structural designs, and "finishes" applied to fabrics often take into consideration, in whole or in part, the desirability of improved "washability". In addition, other external approaches to improve cleaning performance of soiled fabric articles are available. These include relatively simple techniques such as pouring laundry detergent directly on stains just prior to placement in the washing machine and various "home remedies" applied to a stain at the time of its occurrence. Yet another external approach to improved cleaning consists of the application of one of several commercial "pre-spotting" compositions designed for such purpose, either immediately before laundering, immediately after soiling, or at some point in between.
Taken together, this wide array of equipment, cleaning agents and pre-treating techniques have proved adequate in maintaining the pre-eminence of conventional laundry practice while failing to fully satisfy the need for improved cleaning performance as evidenced by the high level of developmental activity which continues in the laundering field. No particular washing machine design has proven to be optimal. No single commercial laundry detergent or combination of detergent and additives has been found capable of cleaning all soil types encountered in a typical wash load. Pre-soak cycles on washing machines are not frequently used due primarily to time constraints. Pre-spotting products and techniques apply only to the worst of stains, and then only if the launderer is highly conscientious. New fabrics and fabric finishes have been unable to resist adherence by persistent soils.
Soiled fabrics which have been set aside for laundering are commonly placed in a hamper designed for this purpose. Hampers are generally designed to "breathe" or allow air exchange so as to prevent biological growth on the fabric articles during storage. While awaiting laundering, stains and soils undergo a progressive tendency to "set", or become more difficult to remove. Dehydration of water-borne soils, whether soluble or suspended, often creates chemical structures which become increasingly difficult to rehydrate. Unsaturated fatty substances, such as those contained in sebum, food particles and unsaturated oils, undergo air oxidation to produce products which adhere much more tenaciously to fabric fibers. Mobile organic soils continue to spread and penetrate fibers over time. The end result upon subsequent laundering of the fabrics so stored is a less than desirable efficiency with respect to removal of such contaminants.